Minimum Return Power Control for Three-Level Dual Active Hybrid Full-Bridge DC-DC Converters

Abstract

Hybrid three-level full bridge (H-TLFB) DC-DC converters increase the input voltage range by introducing a three-level bridge arm. Aimed at the problems of large power return and high current stress in the traditional dual phase shift control, a minimum return power control strategy is proposed. First, the power transmission characteristics of H-TLFB DC-DC converter are analyzed, the size of the return power value of the converter in two different operating modes is compared, and the optimal shift of the return power is calculated according to the mathematical relationship between the return power and the voltage ratio, the shift and the transmission power. The corresponding optimal shift of the return power is calculated, and the corresponding optimization control strategy is designed. Compared with the traditional dual phase shift control strategy, the return power in the minimum return power control strategy can reach the minimum value in the full power transmission range, and within a certain voltage ratio range, the return power and current stress can be optimized at the same time. Finally, the correctness and feasibility of the design control strategy are verified by experiments.

Keywords

• hybrid three-level full bridge (h-tlfb) dc-dc converter
• phase shift control
• backflow power
• transmission efficiency
• current stress